Field
Aspects of the present disclosure relate to semiconductor devices, and more particularly to self-aligned gate contacts for improving metal oxide semiconductor (MOS) varactor quality (Q)-factor.
Background
Mobile radio frequency (RF) chip designs (e.g., mobile RF transceivers) are complicated by the use of passive devices, which directly affect analog/RF performance considerations, including mismatch, noise, and other performance considerations. Passive devices may involve high performance inductor and capacitor components. For example, an RF module (e.g., an RF front end (RFFE) module) may include inductors (L) and capacitors (C) arranged to form filters and other RF devices. Arrangements of these passive devices may be selected to improve device performance, while suppressing unwanted noise (e.g., artificial harmonics) to support advanced RF applications.
The design of mobile RF transceivers may include the use of a voltage-controlled capacitance and/or a tunable capacitor (e.g., a varactor) for advanced RF applications. For example, tunable capacitors may provide RF and impedance matching in RF circuits of advanced RF applications. In these advanced RF technologies, short gate length (Lg) or short-channel MOS varactors having a high quality (Q)-factor are desired. Unfortunately, short-channel/gate length MOS varactors may exhibit an undesirable quality factor due to increased gate resistance.